Compounded lubricating oil



Patented June 15, 1948 COMPOUNDED wnmca'rmo on.

Louis A. Mikeska, Westfield, N. .L, assignor to Standard Oil DevelopmentCompany, a corporation of Delaware No Drawing. Original applicationFebruary19,

1944, Serial No. 523,091. Divided and this application March. 8, 1946,Serial No. 653,152

This invention relates to lubricants and other organic materials subjectto deterioration in the presence of oxygen, and it relates moreparticularly to mineral lubricating oil compositions for 7 Claims. (Cl.25246.6)

rivatives of thiophosphoric and thiophosphorous acids. These arerepresented by the formula:

(E) n (S) a (RX) iP-Sr-P (RX) 1 use as crankcase lubricants for internalcombustion engines and to addition agents suitable for Where is analiphatic, aromatic or aliphaticretarding the deterioration of such oilsand for erometle radical X18 Oxygen Sulfur, n is 0 1, improving otherproperties of the same. This and is an integer from 2 to The radical Rapplication is a division of my copending a ly is preferably ahydrocarbon group, which may be cation Serial No. 523,091, filedFebruary 19, 1944 alkyl, aryl, elkaryl or aralkyl and may contain (nowabandoned) I various substituent groups in place of one or more Inaccordance with the present invention a hydrogen atoms and the oxygen orsulfur atom new class of organic compositions are described of the Rxgroup is attached to caTbOn P of which are particularly useful asadditives for the B group- Ameng t Various substltuent minerallubricating oils used in internal combusatoms d groups Wmel} may beattached to the tion engines, in which they act as inhibitors of Rgroups may be mentlened alkyl. eryl, Y. oxidation and as agents forpromoting engine xyl, hydroxyl, sulfhydryl, nitro, amino, alcleanlinessgenerally.' In serving as inhibitors of dehydokete' ester and halogensubstituted oil deterioration they aid in the prevention of ereeerbongmupsi as as halogen atomsring sticking, piston skirt varnish formation,dep- Typical representative of the new osition of sludge, and the like.They are par-' class of addltlves are the followingi ticularly useful ininhibiting the normal corrosive- 08H" 0,3,1 ness of the oil when incontact with copper-lead, o O cadmium-silver and other similar bearingsnow widely used in automotive engines. These com- 8 /PS-BP\ Ca n poundsare likewise suitable for use as antioxidents in organic materialsgenerally where the organic material is known to be susceptible to Bis[di(octylphenoxy)phosphoms]disulilde deterioration in the presence ofoxygen. 0 3H1" 0 H7 The new class of antioxidant compounds are v aorganic compounds containing both phosphorus @Kfi fi O and sulfurand maybe considered as polysulfide can" P-B-ii-S-P 05H" derivatives oforgano-substituted thiophosphor- 9 Q ous, thiophosphoric,thiophosphonic, thiophosphonous, thiophosphinic and thiophosphinousacids. They may be epresented by the followBis[di(octylphenoxy)thiophosphorus]trisuliide ing general formula:Thenew compositions may be readily prepared by first reacting analcohol, phenol or aliphatic L. )n or aromatic mercaptan with a sulfide-of phosphorus, such as PZSS, P2S 5(P4Sl0), P483, P487 and the like, toform a partially esterified thiophosphorous or thiophosphoric acid, andthen further RQOi h reacting this product as such or in the form of ametal salt with an oxidizing agent or with a in which R and R are thesame or difierent aii- 4 sulfur halide. Thus, when an alcohol is reactedphatic, aromatic or aliphatic-aromatic radicals, with phosphorustrisulfide, a dialkylated mono- X is oxygen or sulfur and is joined to acarbon thiophosphorous acid is formed according to the atom of the R orB group, a, b, and n are 0 or 1, following equation: and a: is aninteger from 2 to 4.

Particularly preferred are the polysulflde de= ROMPSH HIS auaaee Thisalkylated,thiophosphorous acid may then be treated with an oxidizingagent or with sulfur dichloride or sulfur monochloride to form adisulflde, trisulfide or tetrasulflde, respectively, according to thefollowing equations:

Similarly, when the alcohol is reacted with phos phorus pentasulfide,'the corresponding di-substituted dithiophosphoric acid will be formed,and this may likewise be converted into disulflde, trisulflde ortetrasulfide compounds. Suitable alcohols which may be employed includeoctyl alcohol, cetyl alcohol, stearyl alcohol, methyl cyclohexanol,oleyl alcohol, wax alcohols, phenyl ethyl alcohol, phenyl octyl alcohol,and the like. Sulfurized alcohols such as sulfurized oleyl alcohol mayalso be used. Corresponding reactions will take place by starting withmercaptar'is, phenols or thiophenols instead of alcohols. Suitableoxidizing agents for converting the thiophosphorous and thiophosphoricacids to disulfides include iodine, potassium triodide, ferric chloride,sodium hypochlorite, or oxygen itself, but it is not intended that theinvention be limited in any mannor by the oxidizing agent used.

Among the more preferred starting materials are the phenols and theiralkylated derivatives, and the naphthols, as well as derivatives ofthese containing substituents such as halogen,- nitro groups, aminogroups, keto groups, carboxyl groups, ester groups, etc. Typicalpreferred phenolic materials are the cresols, xylenols, mesitol, butylphenol, amyl phenol, diamyl phenol, tertiary octyl phenol, cetyl phenol,octadecyl phenol, cashew nut shell phenol (cardanol), phenyl phenol(hydroxybiphenyl), petroleum phenols, wax alkylated phenols and thelike. Instead of the phenols themselves there may be employed henolsulfides, such as those obtained by reacting phenols with sulfurhalides. Among these phenol sulfides are included tertiary octyl phenolsulfide, di-tertiary amyl phenol sulfide, cetyl phenol sulfide and waxalkylated phenol sulfides.

Suitable products for use in the present invention may also be preparedfrom mixed organo-substituted thioacids of phosphorus, as. for example,those prepared by reaction of a sulfide of phosphorus with a mixture ofa phenol and an alcohol, a phenol and a mercaptan, a phenol sulfide andan alcohol, a phenol and a phenol sulflde, an alcohol and a mercaptan,a. cyclic'alcohol anda straight chain alcohol, etc. Thus, for example, amixture of tertiary octyl phenol sulonly and should not be considered aslimiting the scope of the invention in any way.

Examum: 1

Bis-dioctoxyphosphorus tetrasulflde .520 grams (4 mols) of octyl alcohol(2-ethylhexanol) was added to 158 grams (1 mol) of 'methylcyclohexanoland 500 cc. of dioxane.

P28: in a flask equipped with a'thermometer, stirrer and returncondenser. The mixture was heated to about C., at which temperature avigorous evolution of H28 was noted. The temperature of the reactionmixture was maintained at 80-90 C. untilno more HzS was given oil (about3 hours), while vigorous agitation was maintained. The mixture was thencooled, diluted with ether and filtered to remove a small amount ofinsoluble material. The acid product was neutralized with an alcoholicsolution of NaOH and the solvent was removed under reduced pressure. Theresidue consisted of a soft light colored soap.

70 grams 0/. mol) of the sodium salt formed as described above wasdissolved in cc. of benzene, and 15.3 grams (/2 mol) of S201: in 50 cc.of benzene was added. After stirring for about /2 hour the reactionmixture was washed several times with water, dried and the benzenestripped oil. under atmospheric pressure, leaving 71 grams of a clearstraw colored oil.

Exams: 2

. Bisldfltert-octylphenozy) thiophosphorusl trisulfide A reaction flaskequipped with astirrer and return condenser was charged with 412 grams(2 mols) of tert.-octyl phenol. To this was then added 750 cc. dioxaneand 111 grams /2 mol) Pass. The mixture was refluxed for 3 hours andthen transferred to a distilling flask and the solvent was removed at100 C. and 2 mm. pressure, yielding a light coloredviscous oil. This oilwas transferred to another reaction flask equipped with stirrer, returncondenser and dropping funnel, to which was added 500 cc. of benzol. Thedropping funnel was charged with 48 grams (about mol) of sulfurdichloride. The latter was then added slowly to the reactor with rapidstirring. Some heat was evolved during the addition of the $012. Whenall of this had been added, the heating was'continued until no more HClwas given off, nitrogen being passed through in order to sweep out theHCl. The reaction mixture was transferred to a distilling flask and thesolvent removed at 100 C. and under 3 mm. pressure yielding a lightyellow oil containing 12.88% sulfur and 5.80% phosphorus.

EXAMPLE 3 Bis Edi (methylcyclohexozcy) thiophosphorus] trisulflde Aflask equipped with a stirrer and a return condenser was charged with255 grams of 10- To this was then added 127 grams of Pass. The mixturewas refluxed until no more H23 was given oil (all the P285 dissolving inless than one hour), which required continued heating for a total of 2/2 hours. The reaction mixture was transferred to a distilling'flask andthe solvent was removed at 100 C. and 3 mm. pressure. The residueweighed 346 grams.

340 grams of this product and 500 cc. of benzol were placed in anotherreaction flask, and a mixture of 60 grams of. SC12 and 60 cc. of benzenewas added slowly with rapid stirring. A fair amount of heat was evolvedduring this step. When all the S01: had been added, the mixture wasrefluxed until no more HCl gas was given off, removal of the latterbeing aided by passing nitrogen through the mixture. When the evolutionof hydrogen chloride had ceased (after about 4 hours), the mixture wastransferred to I a distilling flask and the solvent was removed at 100C. and 3 mm. pressure. The residue A mixture of 216 grams (2 mols) ormeta cresol, 500 cc. of toluene, 120 grams of pyridine and 111 gramsmol) of phosphorus pentasulfide was heated at 100 C. under reflux withrapid stirring for 3 hours. The reaction mixture, which now consisted oftwo layers, was filtered to remove asmall amount. of unchanged P285. Thefiltrate was poured into a dilute sodium carbonate solution. The toluenelayer was separated from the aqueous'layer and the latter was extractedwith ether to remove the last traces of unchanged cresol and thenacidified with a little dilute hydrochloric acid. The resulting crudepyridine salt of di-cresyldithiophosphoric acid was extracted withethylene dichloride and the extract was washed with water and finallydried over-sodium sulfate. On removal of the solvent, the residue,consisting of the purified pyridine salt of di-m-cresyldithiophosphoricacid, was obtained as a viscous reddish oil which crystallized onstanding.

50 grams of this pyridine salt was suspended in water and neutralizedwith sodium hydroxide. The solution was treated with aqueous potassiumtriiodide solution until no more iodine was absorbed. The product wasextracted with ether, and the extract was washed several times withdilute hydrochloric acid to remove the pyridine. Finally the etherextract was washed once with dilute sodium hydroxide,-whereupon it wasdried over sodium sulfate. On removal of the ether, 48 grams of thedesired disulfide was obtained as a light colored oil. I

Exams: 5 The Underwood oxidation test was applied to a base oilconsisting of a. solvent extracted paraffinic oil of 47.5 secondsviscosity (Saybolt) at 210 F. and a viscosity index of 113 and to ablend consisting of the same base oil to which BaseO 0.01% Feaoa wasadded to each oil sample. Table I gives the cumulative bearing weightlosses at the end of the 5 hour and 10.hour periods and clearly showsthat the products of the present invention are very eflective corrosioninhibitors.

Table I Cumulative hearing weight loss, on

D 5 hrs. 10 hrs.

' il Base 0il+l Product oi Example 2.--

155 4 Base 0il+l a Product of Example 3 9 EXAMPLE 6 In the followingtests a simple of an unblended base oil consisting of a solventextracted Coastal naphthenic oil of 60 seconds Saybolt viscosity (210F.) and. a sampleof the base oil containing 1% of the product of Example2' were tested in a six cylinder Chevrolet engine run under high speed,high temperature conditions, namely, 30 B. H. P. output, 3150 R. P, M.,280 F. 'oil temperature, 200 F. jacket temperature and an air/fuel ratioof 14.2/1 for periods 01' 36 hours After each test was completed theengine parts were examined and given demerit ratings based on theircondition. The individual demerits were weighted and an overall demeritrating had been added 1% of the product of Example 2,

maintained at-this pressure throughout the test.

As soon as the oil had attained the test temperature of 325 F. theheater and pump were turned oif just long enough to put the alreadyprepared and weighed bearings in place. Two copperlead bearing halveswere used simultaneously in the test. These were attached to a highlypolished copper baiiie approximately 2". x 10" whose function was toaccelerate deterioration of the lubricating oil during the test. At theend of the test period of 5 hours the bearings were removed, cleanedwith naphtha, dried and weighed. A'new copper-lead bearing was thenplaced in the machine and the test conducted for an additional 5 hourperiod. To accelerate corrosion iron 'naphthenate in an equivalent ofcalculated from them. A lower demerit rating indicates a better enginecondition and hence a better performance of the oil in the engine. Theresults are shown in Table II. It will be readily seen that the blendedoil gave a much cleaner engine than did the base oil itself.

Table II Engine Demerits Bearing Wt. Loss (mg. per bearing)- Oil Over-Rin Piston all .Zong Skirts slldge Base Oil Base OiH-l %Prodnot ofExample 2-.

The products of the present invention may be employed not only inordinary hydrocarbon. lubricating oils but also in the heavy duty typeof lubricating oils which have been compounded with such detergent typeadditives as metal soaps, metal petroleum sulfonates, metal phenates,metal alcoholates, metal alkyl phenol sulfides, metal organo phosphates,thiophosphates, phosphites and thiophosphites, metal salicylates, metalxanthates and thioxanthates, metal thiocaramates, reaction products ofmetal phenates and sulfur, reaction products of metal phenates andphosphorus sulfides. metal phenol sulfonates,

and the like. Thus, the polysulflde derivatives of a theorgano-substituted thio acids of phosphorus maybe used in lubricatingoils containing such addition agents as barium tert.-octyl phenolsulfide, calcium tert.-amyl phenol sulfide, nickel oleate, bariumoctadecylate, calcium phenyl'stearate, zinc diisopropylsalicylate,aluminum naphthenate, calcium cetyl phosphate, barium di-tert:

amyl phenol sulfide, calcium petroleum sulfonate,

zinc methyl cyclohexyl thiophosphate, calcium dichlorostearate, etc.

The following are'examples of representative lubricating oilcompositions in which the additives of the present invention areemployed in con- Junction with detergent additives (1) RefinedMid-Continent lubricating oil-plus 1.1% calcium sulfonate 0.8% bis[di(tert.-octylphenoxy) thiophosphorus] trisulfide (2) Solvent extractedCoastal naphthenic oil plus The lubricating oil base stocks used in thecompositions of this invention may be straight minerai lubricating oilsor distillates-derived from paraiiinic, naphthenic, asphaltic or mixedbase crudes, or, if desired, various blended oils may be employed aswell as residuals, particularly those from which asphaltic constituentshave been carefully removed. The oils may be refined by conventionalmethods using acid, alkali and/or clay or other agents such as aluminumchloride, or they may be extracted oils produced, for example, bysolvent extraction with solvents of the type of phenol, sulfur dioxide,furfural, dichloro ethyl ether, nitrobenzene, crotonaldehyde, etc.Hydrogenated oils or white oils may be employed as well as syntheticoils prepared, for example, by the polymerization of olefins or by thereaction of oxides of carbon with hydrogen or by the hydrogenation ofcoal or its products. In certain instances cracking coil tar fractionsand coal tar or shale oil distillates may also be used. Also, forspecial applications, animal, vegetable or fish oils or theirhydrogenated or voltolized products may be employed, either alone or inadmixture with mineral oils.

For the best results the base stock chosen should normally be that oilwhich without the new additives present gives the optimum performance inthe service contemplated. However, since one .vent for the additive,although in some cases auxiliary solvent agents may. be used. Thelubricating oils, however they may have been produced,

may vary considerably in viscosity and other properties depending uponthe particular use for which they are desired, but they usually rangefrom about 40 to 150 seconds Saybolt viscosity at 210 F. For thelubricating of certain low and medium speed Diesel engines the generalpractice has often been to use a lubricating oil base stock preparedfrom naphthenic or aromatic crudes and having a Saybolt viscosity at 210F. of 45 to 90 seconds and'a viscosity index of to. 50. However, incertain types of Diesel service, particularly with high speed Dieselengines, and in aviation engine and other gasoline engine service, oilsof higher viscosity index are often preferred, for example, up

[di(methylcyclohexoxy)phosit is preferable to isolate the alcohols fromthose tallic compounds, metallic or other soaps,- sludge dispersers,antioxidants, thickeners, viscosity index improvers, oiliness agents,resins, rubber, oleiin polymers, voltolized fats, voltolized mineraloils, and/or voltolized waxes and colloidal solids such as graphite orzinc oxide, etc. Solvents and assisting agents, such as esters, ketones,alcohols, aldehydes, halogenated or nitrated compounds, and the like mayalso be employed.

Assisting agents which are particularly desirable are the higheralcohols having eight or more carbon atoms and preferably 12 to 20carbonv atoms;

The alcohols may be saturated straight and branched chain aliphaticalcohols such as octyl alcohol (CaHmOH) lauryl alcohol CmHzsOH) oetylalcohol (CmHasOH), stearyl alcohol, sometimes referred to as octadecylalcohol (Ciel-1370K) heptadecyl alcohol (C1'IH25OH), and the like; thecorresponding olefinic alcohols such as oleyl alcohol; cyclic alcohols,such as naphthenic alcohols; and aryl substituted alkyl alcohols, forinstance, phenyl octyl alcohol, or octadecyl ben'zyl alcohol or mixturesof these various alcohols, which may be pure or substantially puresynthetic alcohols. One may also use mixed naturally occurring alcoholssuch as those found in wool fat (which is known to contain a substantialpercentage of alcohols having, about 16 to 18 carbon atoms) and in spermoil (which contains a high percentage of cetyl alcohol); and althoughlubricants the additives of the present invention may also be used inextreme pressure lubricants,

engine 'fiushing'oils, industrial oils, general machinery oils, processoils, rust preventive compositions and greases. Also their use in motorfuels, Diesel fuels and kerosene is contemplated. A particularapplication in this regard is their use in motor fuels containingtetraethyl lead or other The present invention is not to be considered 5as limited by any of the examples described herein which are given byway of illustration only, but is to be limited solely by the terms ofthe appended claims.

I claim:

1. A mineral lubricating oil containing a small quantity suiilcient tostabilize said oil in the pres- Products prepared syntheticallyv ence ofongen but not greater than about 1% of a compound oi theformula R'(X)|(xmz' where R and R are organic groups selected from the classconsisting of aliphatic, aromatic and aliphatic-aromatic groups, X is amember of the group consisting of oxygen and sulfur and is joined to acarbon atom of group R or R, a, -b and n are each or 1, and a: is aninteger from 2 to 4.

2. A mineral lubricating oil containing a small quantity suflicient tostabilize said oil in the pres- A 2 in which R of the formula is ahydrocarbon group and x is oxygen.

4. A mineral lubricating oil according to claim 2 Y in which R of theformula is a hydrocarbon group,

x is oxygen and x 3.

5. A mineral lubricating oil containing a quantity sufficient tostabilize said oil in the presence of oxygen but not greater than about1% ence of oxygen but not greater than about 1% of a compound of theformula (nxni -st-i mxn joined to a carbon atom of group R, n is 0 or 1,

and a: is an integer from 2 to 4. I

3. A mineral lubricating oil according to claim of his [di(octylphenoxy)thiophosphorusl trisuliide.

s. A mineral lubricatingoil containing a small quantity suflicient tostabilize said oil in the presence of oxy en but not greater than about1% of his [di(methylcyclohexoxy)thiophosphorus] trisulflde.

7. A mineral lubricating oil according to claim 2 in which R or theformula is an alkyl group, 2: is oxygen, n is 1, and a: is an integerfrom 2 to 4.

' LOUIS A; MIKESKA.

REFERENCES cI'rEn The following references are of recordinjhe NumberName Date Osborne Mar. '1, 1944

